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Kulich I, Schmid J, Teplova A, Qi L, Friml J. Rapid translocation of NGR proteins driving polarization of PIN-activating D6 protein kinase during root gravitropism. eLife 2024; 12:RP91523. [PMID: 38441122 PMCID: PMC10942638 DOI: 10.7554/elife.91523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2024] Open
Abstract
Root gravitropic bending represents a fundamental aspect of terrestrial plant physiology. Gravity is perceived by sedimentation of starch-rich plastids (statoliths) to the bottom of the central root cap cells. Following gravity perception, intercellular auxin transport is redirected downwards leading to an asymmetric auxin accumulation at the lower root side causing inhibition of cell expansion, ultimately resulting in downwards bending. How gravity-induced statoliths repositioning is translated into asymmetric auxin distribution remains unclear despite PIN auxin efflux carriers and the Negative Gravitropic Response of roots (NGR) proteins polarize along statolith sedimentation, thus providing a plausible mechanism for auxin flow redirection. In this study, using a functional NGR1-GFP construct, we visualized the NGR1 localization on the statolith surface and plasma membrane (PM) domains in close proximity to the statoliths, correlating with their movements. We determined that NGR1 binding to these PM domains is indispensable for NGR1 functionality and relies on cysteine acylation and adjacent polybasic regions as well as on lipid and sterol PM composition. Detailed timing of the early events following graviperception suggested that both NGR1 repolarization and initial auxin asymmetry precede the visible PIN3 polarization. This discrepancy motivated us to unveil a rapid, NGR-dependent translocation of PIN-activating AGCVIII kinase D6PK towards lower PMs of gravity-perceiving cells, thus providing an attractive model for rapid redirection of auxin fluxes following gravistimulation.
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Affiliation(s)
- Ivan Kulich
- Institute of Science and Technology AustriaKlosterneuburgAustria
| | - Julia Schmid
- Institute of Science and Technology AustriaKlosterneuburgAustria
| | | | - Linlin Qi
- Institute of Science and Technology AustriaKlosterneuburgAustria
| | - Jiří Friml
- Institute of Science and Technology AustriaKlosterneuburgAustria
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2
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Wallner ES, Dolan L, Bergmann DC. Arabidopsis stomatal lineage cells establish bipolarity and segregate differential signaling capacity to regulate stem cell potential. Dev Cell 2023; 58:1643-1656.e5. [PMID: 37607546 DOI: 10.1016/j.devcel.2023.07.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 04/04/2023] [Accepted: 07/31/2023] [Indexed: 08/24/2023]
Abstract
Cell polarity combined with asymmetric cell divisions (ACDs) generates cellular diversity. In the Arabidopsis stomatal lineage, a single cortical polarity domain marked by BASL orients ACDs and is segregated to the larger daughter to enforce cell fate. We discovered a second, oppositely positioned polarity domain defined by OCTOPUS-LIKE (OPL) proteins, which forms prior to ACD and is segregated to the smaller (meristemoid) daughter. Genetic and misexpression analyses show that OPLs promote meristemoid-amplifying divisions and delay stomatal fate progression. Polarity mediates OPL segregation into meristemoids but is not required for OPL function. OPL localization and activity are largely independent of other stomatal polarity genes and of the brassinosteroid signaling components associated with OPLs in other contexts. While OPLs are unique to seed plants, ectopic expression in the liverwort Marchantia suppressed epidermal fate progression, suggesting that OPLs engage ancient and broadly conserved pathways to regulate cell division and cell fate.
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Affiliation(s)
- Eva-Sophie Wallner
- Department of Biology, Stanford University, Stanford, CA 94305-5020, USA; Gregor Mendel Institute, Dr.-Bohr-Gasse 3, 1030 Wien, Austria; Howard Hughes Medical Institute, Stanford, CA 94305, USA.
| | - Liam Dolan
- Gregor Mendel Institute, Dr.-Bohr-Gasse 3, 1030 Wien, Austria
| | - Dominique C Bergmann
- Department of Biology, Stanford University, Stanford, CA 94305-5020, USA; Howard Hughes Medical Institute, Stanford, CA 94305, USA.
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3
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Nishimura T, Mori S, Shikata H, Nakamura M, Hashiguchi Y, Abe Y, Hagihara T, Yoshikawa HY, Toyota M, Higaki T, Morita MT. Cell polarity linked to gravity sensing is generated by LZY translocation from statoliths to the plasma membrane. Science 2023; 381:1006-1010. [PMID: 37561884 DOI: 10.1126/science.adh9978] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 08/02/2023] [Indexed: 08/12/2023]
Abstract
Organisms have evolved under gravitational force, and many sense the direction of gravity by means of statoliths in specialized cells. In flowering plants, starch-accumulating plastids, known as amyloplasts, act as statoliths to facilitate downstream gravitropism. The gravity-sensing mechanism has long been considered a mechanosensing process by which amyloplasts transmit forces to intracellular structures, but the molecular mechanism underlying this has not been elucidated. We show here that LAZY1-LIKE (LZY) family proteins involved in statocyte gravity signaling associate with amyloplasts and the proximal plasma membrane. This results in polar localization according to the direction of gravity. We propose a gravity-sensing mechanism by which LZY translocation to the plasma membrane signals the direction of gravity by transmitting information on the position of amyloplasts.
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Affiliation(s)
- Takeshi Nishimura
- Division of Plant Environmental Responses, National Institute for Basic Biology, Okazaki 444-8585, Japan
- Course for Basic Biology, The Graduate Institute for Advanced Studies, SOKENDAI, Hayama 240-0115, Japan
| | - Shogo Mori
- Division of Plant Environmental Responses, National Institute for Basic Biology, Okazaki 444-8585, Japan
| | - Hiromasa Shikata
- Division of Plant Environmental Responses, National Institute for Basic Biology, Okazaki 444-8585, Japan
- Course for Basic Biology, The Graduate Institute for Advanced Studies, SOKENDAI, Hayama 240-0115, Japan
| | - Moritaka Nakamura
- Division of Plant Environmental Responses, National Institute for Basic Biology, Okazaki 444-8585, Japan
| | - Yasuko Hashiguchi
- Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan
| | - Yoshinori Abe
- Department of Biochemistry and Molecular Biology, Saitama University, Saitama 338-8570, Japan
| | - Takuma Hagihara
- Department of Biochemistry and Molecular Biology, Saitama University, Saitama 338-8570, Japan
| | | | - Masatsugu Toyota
- Department of Biochemistry and Molecular Biology, Saitama University, Saitama 338-8570, Japan
- Suntory Rising Stars Encouragement Program in Life Sciences (SunRiSE), Suntory Foundation for Life Sciences, Kyoto 619-0284, Japan
- Department of Botany, University of Wisconsin, Madison, WI 53706, USA
| | - Takumi Higaki
- Faculty of Advanced Science and Technology, Kumamoto University, Kumamoto 860-8555, Japan
- International Research Organization for Advanced Science and Technology, Kumamoto University, Kumamoto 860-8555, Japan
| | - Miyo Terao Morita
- Division of Plant Environmental Responses, National Institute for Basic Biology, Okazaki 444-8585, Japan
- Course for Basic Biology, The Graduate Institute for Advanced Studies, SOKENDAI, Hayama 240-0115, Japan
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4
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Liya DH, Anand NM, Jainarayanan AK, Elanchezhian M, Seetharaman M, Balakannan D, Pradhan AK. Drug repurposing and sequence analysis in S-glycoprotein variants reveals critical signature patterns and destabilization of receptor-binding domain in omicron variant. J Biomol Struct Dyn 2023; 41:7931-7948. [PMID: 36173706 DOI: 10.1080/07391102.2022.2127902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Accepted: 09/17/2022] [Indexed: 10/14/2022]
Abstract
The evolution of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus since its emergence in 2019 has yielded several new viral variants with varied infectivity, disease severity, and antigenicity. Although most mutations are expected to be relatively neutral, mutations at the Spike region of the genome have shown to have a major impact on the viral transmission and infection in humans. Therefore, it is crucial to survey the structures of spike protein across the global virus population to contextualize the rate of therapeutic success against these variants. In this study, high-frequency mutational variants from different geographic regions were pooled in order to study the structural evolution of the spike protein through drug docking and MD simulations. We investigated the mutational burden in the spike subregions and have observed that the different variants harbour unique signature patterns in the spike subregions, with certain domains being highly prone to mutations. Further, the MD simulations and docking study revealed that different variants show differential stability when docked for the same set of drug targets. This work sheds light on the mutational burden and the stability landscape of the spike protein across the variants from different geographical regions.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Devang Haresh Liya
- Department of Physical Sciences, Indian Institute of Science Education and Research, Mohali, Manauli, India
| | - Nithishwer Mouroug Anand
- Department of Physical Sciences, Indian Institute of Science Education and Research, Mohali, Manauli, India
| | - Ashwin Kumar Jainarayanan
- Kennedy Institute of Rheumatology, University of Oxford, Oxford, UK
- Interdisciplinary Bioscience Doctoral Training Program and Exeter College, University of Oxford, Oxford, UK
| | - Mirudula Elanchezhian
- Department of Biological Sciences, Indian Institute of Science Education and Research, Mohali, Manauli, India
| | - Madhumati Seetharaman
- Department of Physical Sciences, Indian Institute of Science Education and Research, Mohali, Manauli, India
| | - Dhanuush Balakannan
- Department of Biological Sciences, Indian Institute of Science Education and Research, Mohali, Manauli, India
| | - Arpit Kumar Pradhan
- Klinik für Anaesthesiologie und Intensivmedizin der Technischen Universität München, Klinikum rechts der Isar, Munchen, Germany
- Graduate School of Systemic Neuroscience, Ludwig Maximilian University of Munich, Munchen, Germany
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5
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Khatoon U, Prasad V, Sawant SV. Expression dynamics and a loss-of-function of Arabidopsis RabC1 GTPase unveil its role in plant growth and seed development. PLANTA 2023; 257:89. [PMID: 36988700 DOI: 10.1007/s00425-023-04122-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 03/16/2023] [Indexed: 06/19/2023]
Abstract
Transcript isoform dynamics, spatiotemporal expression, and mutational analysis uncover that Arabidopsis RabC1 GTPase is required for root length, flowering time, seed size, and seed mucilage. Rab GTPases are crucial regulators for moving different molecules to their specific compartments according to the needs of the cell. In this work, we illustrate the role of RabC1 GTPase in Arabidopsis growth and seed development. We identify and analyze the expression pattern of three transcript isoforms of RabC1 in different development stages, along with their tissue-specific transcript abundance. The promoter activity of RabC1 using promoter-GUS fusion shows that it is widely expressed during the growth of Arabidopsis, particularly in seed tissues such as chalazal seed coat and chalazal endosperm. Lack of RabC1 function led to shorter roots, lesser biomass, delayed flowering, and sluggish plant development. The mutants had smaller seeds than the wildtype, less seed mass, and lower seed coat permeability. Developing seeds also revealed a smaller endosperm cavity and shorter integument cells. Additionally, we found that the knock-out mutant had downregulated expression of genes implicated in the transit of sugars and amino acids from maternal tissue to developing seed. The seeds of the loss-of-function mutant had reduced seed mucilage. All the observed mutant phenotypes were restored in the complemented lines confirming the function of RabC1 in seed development and plant growth.
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Affiliation(s)
- Uzma Khatoon
- Plant Molecular Biology and Biotechnology Division, CSIR-National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226001, India
- Department of Botany, University of Lucknow, Lucknow, 226007, India
| | - Vivek Prasad
- Department of Botany, University of Lucknow, Lucknow, 226007, India
| | - Samir V Sawant
- Plant Molecular Biology and Biotechnology Division, CSIR-National Botanical Research Institute, Rana Pratap Marg, Lucknow, 226001, India.
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6
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Kawamoto N, Morita MT. Gravity sensing and responses in the coordination of the shoot gravitropic setpoint angle. THE NEW PHYTOLOGIST 2022; 236:1637-1654. [PMID: 36089891 PMCID: PMC9828789 DOI: 10.1111/nph.18474] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 08/13/2022] [Indexed: 06/15/2023]
Abstract
Gravity is one of the fundamental environmental cues that affect plant development. Indeed, the plant architecture in the shoots and roots is modulated by gravity. Stems grow vertically upward, whereas lateral organs, such as the lateral branches in shoots, tend to grow at a specific angle according to a gravity vector known as the gravitropic setpoint angle (GSA). During this process, gravity is sensed in specialised gravity-sensing cells named statocytes, which convert gravity information into biochemical signals, leading to asymmetric auxin distribution and driving asymmetric cell division/expansion in the organs to achieve gravitropism. As a hypothetical offset mechanism against gravitropism to determine the GSA, the anti-gravitropic offset (AGO) has been proposed. According to this concept, the GSA is a balance of two antagonistic growth components, that is gravitropism and the AGO. Although the nature of the AGO has not been clarified, studies have suggested that gravitropism and the AGO share a common gravity-sensing mechanism in statocytes. This review discusses the molecular mechanisms underlying gravitropism as well as the hypothetical AGO in the control of the GSA.
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Affiliation(s)
- Nozomi Kawamoto
- Division of Plant Environmental ResponsesNational Institute for Basic BiologyMyodaijiOkazaki444‐8556Japan
| | - Miyo Terao Morita
- Division of Plant Environmental ResponsesNational Institute for Basic BiologyMyodaijiOkazaki444‐8556Japan
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7
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Koh SWH, Diaz-Ardila HN, Bascom CS, Berenguer E, Ingram G, Estelle M, Hardtke CS. Heterologous expression of a lycophyte protein enhances angiosperm seedling vigor. Development 2022; 149:dev200917. [PMID: 36196593 PMCID: PMC10655917 DOI: 10.1242/dev.200917] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Accepted: 09/26/2022] [Indexed: 03/15/2023]
Abstract
Seedling vigor is a key agronomic trait that determines juvenile plant performance. Angiosperm seeds develop inside fruits and are connected to the mother plant through vascular tissues. Their formation requires plant-specific genes, such as BREVIS RADIX (BRX) in Arabidopsis thaliana roots. BRX family proteins are found throughout the euphyllophytes but also occur in non-vascular bryophytes and non-seed lycophytes. They consist of four conserved domains, including the tandem BRX domains. We found that bryophyte or lycophyte BRX homologs can only partially substitute for Arabidopsis BRX (AtBRX) because they miss key features in the linker between the BRX domains. Intriguingly, however, expression of a BRX homolog from the lycophyte Selaginella moellendorffii (SmBRX) in an A. thaliana wild-type background confers robustly enhanced root growth vigor that persists throughout the life cycle. This effect can be traced to a substantial increase in seed and embryo size, is associated with enhanced vascular tissue proliferation, and can be reproduced with a modified, SmBRX-like variant of AtBRX. Our results thus suggest that BRX variants can boost seedling vigor and shed light on the activity of ancient, non-angiosperm BRX family proteins.
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Affiliation(s)
- Samuel W. H. Koh
- Department of Plant Molecular Biology, University of Lausanne, CH-1015 Lausanne, Switzerland
| | | | - Carlisle S. Bascom
- Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093, USA
| | - Eduardo Berenguer
- Laboratoire Reproduction et Développement des Plantes, ENS de Lyon, 69364 Lyon, France
| | - Gwyneth Ingram
- Laboratoire Reproduction et Développement des Plantes, ENS de Lyon, 69364 Lyon, France
| | - Mark Estelle
- Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093, USA
| | - Christian S. Hardtke
- Department of Plant Molecular Biology, University of Lausanne, CH-1015 Lausanne, Switzerland
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8
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Liu P, Fang Y, Tan X, Hu Z, Jin Y, Yi Z, He K, Wei C, Chen R, Zhao H. Local endocytosis of sucrose transporter 2 in duckweed reveals the role of sucrose transporter 2 in guard cells. FRONTIERS IN PLANT SCIENCE 2022; 13:996618. [PMID: 36352881 PMCID: PMC9638040 DOI: 10.3389/fpls.2022.996618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 10/06/2022] [Indexed: 06/16/2023]
Abstract
The local endocytosis of membrane proteins is critical for many physiological processes in plants, including the regulation of growth, development, nutrient absorption, and osmotic stress response. Much of our knowledge on the local endocytosis of plasma membrane (PM) protein only focuses on the polar growth of pollen tubes in plants and neuronal axon in animals. However, the role of local endocytosis of PM proteins in guard cells has not yet been researched. Here, we first cloned duckweed SUT2 (sucrose transporter 2) protein and then conducted subcellular and histological localization of the protein. Our results indicated that LpSUT2 (Landoltia punctata 0202 SUT2) is a PM protein highly expressed on guard cells. In vitro experiments on WT (wild type) lines treated with high sucrose concentration showed that the content of ROS (reactive oxygen species) in guard cells increased and stomatal conductance decreased. We observed the same results in the lines after overexpression of the LpSUT2 gene with newfound local endocytosis of LpSUT2. The local endocytosis mainly showed that LpSUT2 was uniformly distributed on the PM of guard cells in the early stage of development, and was only distributed in the endomembrane of guard cells in the mature stage. Therefore, we found the phenomenon of guard cell LpSUT2 local endocytosis through the changes of duckweed stomata and concluded that LpSUT2 local endocytosis might be dependent on ROS accumulation in the development of duckweed guard cells. This paper might provide future references for the genetic improvement and water-use efficiency in other crops.
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Affiliation(s)
- Penghui Liu
- CAS Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yang Fang
- CAS Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
| | - Xiao Tan
- CAS Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Zhubin Hu
- CAS Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yanling Jin
- CAS Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
| | - Zhuolin Yi
- CAS Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
| | - Kaize He
- CAS Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
| | - Cuicui Wei
- CAS Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Rui Chen
- CAS Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Hai Zhao
- CAS Key Laboratory of Environmental and Applied Microbiology, Environmental Microbiology Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
- University of Chinese Academy of Sciences, Beijing, China
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9
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Conserved signalling components coordinate epidermal patterning and cuticle deposition in barley. Nat Commun 2022; 13:6050. [PMID: 36229435 PMCID: PMC9561702 DOI: 10.1038/s41467-022-33300-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 09/12/2022] [Indexed: 12/24/2022] Open
Abstract
Faced with terrestrial threats, land plants seal their aerial surfaces with a lipid-rich cuticle. To breathe, plants interrupt their cuticles with adjustable epidermal pores, called stomata, that regulate gas exchange, and develop other specialised epidermal cells such as defensive hairs. Mechanisms coordinating epidermal features remain poorly understood. Addressing this, we studied two loci whose allelic variation causes both cuticular wax-deficiency and misarranged stomata in barley, identifying the underlying genes, Cer-g/ HvYDA1, encoding a YODA-like (YDA) MAPKKK, and Cer-s/ HvBRX-Solo, encoding a single BREVIS-RADIX (BRX) domain protein. Both genes control cuticular integrity, the spacing and identity of epidermal cells, and barley's distinctive epicuticular wax blooms, as well as stomatal patterning in elevated CO2 conditions. Genetic analyses revealed epistatic and modifying relationships between HvYDA1 and HvBRX-Solo, intimating that their products participate in interacting pathway(s) linking epidermal patterning with cuticular properties in barley. This may represent a mechanism for coordinating multiple adaptive features of the land plant epidermis in a cultivated cereal.
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10
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Linh NM, Scarpella E. Leaf vein patterning is regulated by the aperture of plasmodesmata intercellular channels. PLoS Biol 2022; 20:e3001781. [PMID: 36166438 PMCID: PMC9514613 DOI: 10.1371/journal.pbio.3001781] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 08/03/2022] [Indexed: 02/03/2023] Open
Abstract
To form tissue networks, animal cells migrate and interact through proteins protruding from their plasma membranes. Plant cells can do neither, yet plants form vein networks. How plants do so is unclear, but veins are thought to form by the coordinated action of the polar transport and signal transduction of the plant hormone auxin. However, plants inhibited in both pathways still form veins. Patterning of vascular cells into veins is instead prevented in mutants lacking the function of the GNOM (GN) regulator of auxin transport and signaling, suggesting the existence of at least one more GN-dependent vein-patterning pathway. Here we show that in Arabidopsis such a pathway depends on the movement of auxin or an auxin-dependent signal through plasmodesmata (PDs) intercellular channels. PD permeability is high where veins are forming, lowers between veins and nonvascular tissues, but remains high between vein cells. Impaired ability to regulate PD aperture leads to defects in auxin transport and signaling, ultimately leading to vein patterning defects that are enhanced by inhibition of auxin transport or signaling. GN controls PD aperture regulation, and simultaneous inhibition of auxin signaling, auxin transport, and regulated PD aperture phenocopies null gn mutants. Therefore, veins are patterned by the coordinated action of three GN-dependent pathways: auxin signaling, polar auxin transport, and movement of auxin or an auxin-dependent signal through PDs. Such a mechanism of tissue network formation is unprecedented in multicellular organisms. How do plants form vein networks, in the absence of cellular migration or direct cell-cell interaction? This study shows that a GNOM-dependent combination of polar auxin transport, auxin signal transduction, and movement of an auxin signal through plasmodesmata patterns leaf vascular cells into veins.
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Affiliation(s)
- Nguyen Manh Linh
- Department of Biological Sciences, University of Alberta, Edmonton, Canada
| | - Enrico Scarpella
- Department of Biological Sciences, University of Alberta, Edmonton, Canada
- * E-mail:
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11
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Guo X, Dong J. Protein polarization: Spatiotemporal precisions in cell division and differentiation. CURRENT OPINION IN PLANT BIOLOGY 2022; 68:102257. [PMID: 35816992 PMCID: PMC9968528 DOI: 10.1016/j.pbi.2022.102257] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 05/01/2022] [Accepted: 06/01/2022] [Indexed: 05/16/2023]
Abstract
Specification of cell polarity is vital to normal cell growth, morphogenesis, and function. As other eukaryotes, plants generate cellular polarity that is coordinated with tissue polarity and organ axes. In development, new cell types are generated by stem-cell division and differentiation, a process often involving proteins that are polarized to cortical domains at the plasma membrane. In the past decade, pioneering work using the model plant Arabidopsis identified multiple proteins that are polarized in dividing cells to instruct divisional behaviors and/or specify cell fates. In this review, we use these polarized cell-division regulators as example to summarize key mechanisms underlying protein polarization in plant cells. Recent progress underscores that self-organizing amplification processes are commonly involved in establishing cell polarity, and cellular polarity is influenced by both tissue-level and local mechanochemical cues. In addition, protein polarization during asymmetric cell division shows a distinct feature of temporal control in the stomatal lineage. We further discuss possible coordination between protein polarization and the progression of cell cycle in this developmental context.
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Affiliation(s)
- Xiaoyu Guo
- Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA.
| | - Juan Dong
- Waksman Institute of Microbiology, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA; Department of Plant Biology, Rutgers, The State University of New Jersey, New Brunswick, NJ 08901, USA.
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12
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Zhang H, Wang X, Yu HB, Douglas JF. Dynamic heterogeneity, cooperative motion, and Johari-Goldstein [Formula: see text]-relaxation in a metallic glass-forming material exhibiting a fragile-to-strong transition. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2021; 44:56. [PMID: 33871722 DOI: 10.1140/epje/s10189-021-00060-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 03/21/2021] [Indexed: 06/12/2023]
Abstract
We investigate the Johari-Goldstein (JG) [Formula: see text]-relaxation process in a model metallic glass-forming (GF) material ([Formula: see text]), previously studied extensively by both frequency-dependent mechanical measurements and simulation studies devoted to equilibrium properties, by molecular dynamics simulations based on validated and optimized interatomic potentials with the primary aim of better understanding the nature of this universal relaxation process from a dynamic heterogeneity (DH) perspective. The present relatively low temperature and long-time simulations reveal a direct correspondence between the JG [Formula: see text]-relaxation time [Formula: see text] and the lifetime of the mobile particle clusters [Formula: see text], defined as in previous DH studies, a relationship dual to the corresponding previously observed relationship between the [Formula: see text]-relaxation time [Formula: see text] and the lifetime of immobile particle clusters [Formula: see text]. Moreover, we find that the average diffusion coefficient D nearly coincides with [Formula: see text] of the smaller atomic species (Al) and that the 'hopping time' associated with D coincides with [Formula: see text] to within numerical uncertainty, both trends being in accord with experimental studies. This indicates that the JG [Formula: see text]-relaxation is dominated by the smaller atomic species and the observation of a direct relation between this relaxation process and rate of molecular diffusion in GF materials at low temperatures where the JG [Formula: see text]-relaxation becomes the prevalent mode of structural relaxation. As an unanticipated aspect of our study, we find that [Formula: see text] exhibits fragile-to-strong (FS) glass formation, as found in many other metallic GF liquids, but this fact does not greatly alter the geometrical nature of DH in this material and the relation of DH to dynamical properties. On the other hand, the temperature dependence of the DH and dynamical properties, such as the structural relaxation time, can be significantly altered from 'ordinary' GF liquids.
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Affiliation(s)
- Hao Zhang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada.
| | - Xinyi Wang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada
| | - Hai-Bin Yu
- Wuhan National High Magnetic Field Center, Huazhong University of Science and Technology, Wuhan, 430074, Hubei, China
| | - Jack F Douglas
- Material Measurement Laboratory, Materials Science and Engineering Division, National Institute of Standards and Technology(NIST), Gaithersburg, MD, 20899, USA.
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